Blood port assembly and method

ABSTRACT

AN EXTRACORPOREAL HEMODIALYZER INCLUDES AT LEAST ONE NOVEL GENERALLY RIGID BLOOD PORT COMMUNICATING A PATOENT&#39;&#39;S BLOOD INTO AND OUT OF A TUBULAR MEMBRANE COMPRISING PART OF THE HEMODIALYZER. THE BLOOD PORT HAS A CONTOURED EXTERIOR ELEMENT WHICH IS INSERTED INTO THE TUBULAR MEMBRANE. A REFERENCE TAB IS FORMED ON THE BLOOD PORT AND IS SITUATED ADJACENT A FIXED GUIDE TO ESTABLISH A PROPER ORIENTATION FOR THE BLOOD PORT. A SEAL IS FORMED BETWEEN THE MEMBRANE AND THE BLOOD PORT WHEN THE BLOOD PORT IS INSERTED BETWEEN CORRESPONDINGLY CONTOURED SLIDING MEMBERS WHICH ARE THEREAFTER URGED TIGHTLY TOGETHER. THE SLIDING MEMBERS MAY BE SET INTO A CHANNEL IN THE EXTERIOR WALL OF THE HEMODIALYZER AND URGED UPON THE BLOOD PORT BY A LEVER-ACTION CLAMP. AN IMPROVED METHOD OF ATTACHING THE MEMBRANE TO THE BLOOD PORT INCLUDES THE STEPS OF INSERTING THE BLOOD PORT INTO THE TUBULAR MEMBRANE SO THAT A REFERENCE TAB AND COUPLING ELEMENT ARE EXPOSED AND THEREAFTER CREATING A FLUID SEAL BETWEEN THE BLOOD PORT AND THE MEMBRANE.

July 23, 1974 D. 1.. RADFORD- BLOOD PORT ASSEMBLY AND METHOD 2 sheetss neet 1 Filed April 11, 1972 FIG. 3

D. L.. RADFORD BLOOD PORT ASSEMBLY AND METHOD July 23, 1974 2 Sheets-Sheot 2 Filed April 11 1972 M 4 A My v FIG. 4

FIG. 5

United States Patent 3,825,492 BLOOD PORT ASSEMBLY AND METHOD David L. Radford, Salt Lake City, Utah, assignor to Vital Assists, Inc., Salt Lake City, Utah Continuation-impart of application Ser. No. 106,18 l, Jan. 13, 1971, now Patent No. 3,723,305. This apphcatlon Apr. 11, 1972, Ser. No. 243,016

Int. Cl. B01d 13/00 US. Cl. 21022 16 Claims ABSTRACT OF THE DISCLOSURE An extracorporeal hemodialyzer includes at least one novel generally rigid blood port communicating a patients blood into and out of a tubular membrane comprising part of the hemodialyzer. The blood port has a contoured exterior element which is inserted into the tubular membrane. A reference tab is formed on the blood port and is situated adjacent a fixed guide to establish a proper orientation for the blood port. A seal is formed between the membrane and the blood port when the blood port is inserted between correspondingly contoured sliding members which are thereafter urged tightly together. The sliding members may be set into a channel in the exterior wall of the hemodialyzer and urged upon the blood port by a lever-action clamp. An improved method of attaching the membrane to the blood port includes the steps of inserting the blood port into the tubular membrane so that a reference tab and coupling element are exposed and thereafter creating a fluid seal between the blood port and the membrane.

BACKGROUND Field of the Invention The present invention relates to an improved extracorporeal hemodialyzer and more particularly to novel method and apparatus for forming a fluid-tight seal between a tubular membrane and a novel blood port for use in a hemodialyzing apparatus and, further, novel method and apparatus for precisely determining a preferred orientation of the blood port during use.

This application is a continuation-in-part of my copending application Ser. No. 106,184, now Pat. No. 3,723,- 305, filed Jan. 13, 1971.

The Prior Art Historically, kidney diseases have been of critical concern to human life. Many kinds of kidney diseases interfere with the function of the kidney such that the kidney ceases to remove waste and excess water from the "blood. When the kidney is sufiiciently impaired that a large portion of the waste products and water are not removed from the blood, the life of the patient cannot be preserved unless a way is provided for artificially performing the function of the impaired kidney.

All artificial kidneys, sometimes called hemodialyzers, are based upon the principle that waste materials can be removed by dialysis through a membrane through which desirable blood components do not pass. In an artificial kidney, blood having a relatively high concentration of waste products is conducted along a membrane one side of which is exposed to a dialysate fluid having a very low concentration of waste products. Waste products will migrate from the high concentration fluid (blood) through the membrane to the low concentration fluid (dialysate). Excess water can at the same time be removed by maintaining a positive pressure differential between the blood and the dialysate fluid on the opposite side of the membrane.

In my copending patent application aforementioned, blood is pumped along a circuitous path through a tubular ice membrane. It has been found, however, that much diificulty has been associated with the ports which communicate a patients blood into and out of the membrane. The most common problem associated with the prior art blood ports centers on leakage of blood from within the membrane around the membrane-port juncture. This occurs because, conventionally, the membrane is bunched or gathered around a comparatively small annular attachment site forming part of the blood port. The bunching makes a tight fluid seal extremely ditficult so that there is risk of blood leakage into the dialysate solution. Moreover, bunching or gathering of the membrane around the attachment site of the blood port creates a large number of irregular folds and creases in the membrane fabric.

When the membrane is thereafter subjected to relatively high pressures, the folds and creases form weakened areas which frequently rupture when subjected to elevated blood pressures normally existing within the membrane. Historically, membrane rupture has represented a lethal hazard toward which a great deal of attention has been directed whenever extracorporeal hemodialysis is used.

Another common disadvantage of conventional blood ports relates to the tendency of conventional blood ports to be inadvertently bumped or moved from a preferred orientation resulting in stress on the membrane which can produce blood leakage and/ or membrane rupture. For example, blood ports which project outwardly during use can be easily bumped or displaced by persons atending the patient or by hemodialysis support equipment commonly used during the dialysisprocess.

In addition, axial forces exerted upon the blood port when connecting blood lines are forced onto the port or removed from the port tend to cause relative movement between the blood port, per se, and the associated membrane. In each instance, movement of the blood port relative to the hemodialyzer and/or relative to its associated tubular membrane increases the risk that the membrane will be subjected to stress at the connection site.

A significant modification to internal blood port configuration is described in a service manual prepared by Medizintechnische Gerate, Paul Scheibner KG, DDR 9402 Bernsbach, Beierfelder Strasse 18. Despite the mentioned advancement in blood port configuration, until this present invention no simple and effective method and apparatus preserving the orientation of a blood port has been known. Further, an effective way of sealing the tubular membrane to the blood port has not, until this present invention, been devised.

BRIEF DESCRIPTION AND OBJECTS OF THE INVENTION The present invention includes a novel apparatus and method for developing a secure fluid seal between the membrane and the blood port and for preserving the blood port in a predetermined orientation. The secure fluid seal is uniquely maintained when opposed lateral forces are essentially uniformly exerted over a portion of the blood port structure upon which the tubular membrane is superimposed. Unique structure and method are provided for advance setting of the desired amount of force to be exerted upon the blood port.

It is therefore a primary object of the present invention to provide improved extracorporeal hemodialyzing apparatus.

It is another primary object of the present invention to provide novel method of forming a fluid seal between the membrane and the blood port.

Still one further object of the present invention is to provide novel method and apparatus for referencing a blood port to a predetermined location and orientation.

Another significant object of the present invention is to provide improved apparatus and method for facile assembly and disassembly of the blood port and port securing structure.

It is another valuable object of this invention to provide an improved blood port configuration.

Another important object is to provide novel method and apparatus for exerting a generally uniform pressure upon selected portions of the blood port, when in the assembled condition.

These and other objects and features of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary exploded perspective illustration of a presently preferred embodiment of the blood port assembly, portions being broken away to reveal inner parts;

FIG. 2 is a perspective view of one presently preferred blood port and corresponding orientation or reference block embodiment;

FIG. 3 is a perspective view of another presently preferred blood port embodiment with membrane attached and referenced to another presently preferred orientation or reference block embodiment;

FIG. 4 is a vertical cross-section taken along line 44 of FIG. 1; and

FIG. 5 is a fragmentary perspective View of a presently preferred membrane support embodiment with a contoured channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is now made to the illustrated embodiments of the invention comprising FIGS. 1-5, like parts having like numerals throughout.

The Apparatus Referring particularly to FIG. 1, a hemodialyzing vessel generally designated 22 has side walls 24 and end walls 26. While the vessel 22 may be formed of any suitable rigid construction material, transparent plastic is presently preferred. Side wall 24 has an upper edge 28, and end wall 26 has an upper edge 30. The end wall 26 has, in the illustrated embodiment, two spaced apertures; an upper aperture 48 (shown only in FIG. 4) and a lower aperture 50 (shown only in FIG. 1). The apertures are to provide access to the blood-carrying membrane within the hemodialyzing vessel 22 as will be more fully described. Preferably, the apertures are oval in configuration and are sufficiently wide to allow finger access through the end wall 26 during the procedure of assembling the components of the hemodialyzer 22.

As best shown in FIG. 4, the aperture 48 has a downwardly tapered lower edge 49 which communicates the aperture with at least one vertical channel 51. The described arrangement is advantageous because dialysate solution which accumulates around the aperture 48 during the assembly process, as will hereinafter appear, can be easily transported into a dialysate reservoir without leaking outside of the hemodialyzing vessel 22.

Reference blocks 70 and 84, preferably formed of transparent plastic material, are rigidly mounted upon the end wall 26 immediately beneath the corresponding apertures 48 and 50. The reference blocks may be identical, although two different varieties are illustrated in the Figures.

Reference block 70 is provided with side-by-side reference pegs 68 preferably aligned with the axis of aperture 48. Reference block 84 has a single reference peg 82 centrally located in a recess 79. The recess 79 presents shoulders which function as a guide for blood port element 54, as will be subsequently more fully described.

While the reference blocks and 84 are, in the illustrated embodiments, integral with the end wall 26, it should be appreciated that any suitable way of situating the reference blocks at the end wall 26 could be used as long as the reference blocks are maintained in a fixed position with regard to the apertures 48 and 50, during use. Further, while a plurality of reference pegs or a reference peg and recess are, in the illustrated embodiments, used to fix the orientation of the port element 54, any suitable structure could be used which prevents inadvertent lateral or axial displacement of the port element 54 relative to the hemodialyzing vessel 22.

The end wall 26 has a vertically oriented slot generally designated 32 which opens to the interior of the hemodialyzing vessel 22 along essentially the entire length of the side wall 26 and also opens at the upper edge 30'. The slot 32 is spaced from the front and rear side walls 24 of the hemodialyzing vessel 22 so that the axis of the apertures 48 and 50 essentially bisect the longest axis of the slot. Slot 32 has edges 34 which taper inwardly toward the inside surface 35 of end wall 26. Thus, the opening at the inside surface 35 is more narrow than the width of the slot 32 at its base 33. It should also be appreciated that the slot may be oriented in any other suitable direction.

The slot 32 receives complementarily configurated slides 36, 38 and '40 in mating relation. Each slide 36, 38 and 40 is vertically displaceable along the slot 32 and can be removed from the slot 32 by placing a tool or finger against the slide 36, 38 or 40 and lifting one or more of the slides out of the slot 32 at the edge 30. Although the slides 36, 38 and 40 are displaceable in the slot 32, each fits sufliciently tightly that lateral movement is pre cluded. At least one contoured cap generally described 42 and preferably composed of a resilient plastic material is mounted on each of the sildes 36, 38 and 40. While any desirable mounting technique could be used, in the illustrated embodiment, cylindrical projections 44, shown best in FIG. 4, are forced into mating apertures 45 in the corresponding end surfaces of the slides 36, 38 and 40. This mounting technique advantageously accommodates facile replacement of the caps 42 without simultaneous replacement of all slides 36, 38 and 40. Also, because the cap 42 can be formed apart from slides 36, 38 and 40, the contoured portion of each cap 42 can be precision-made by techniques which are both more rapid and less expensive.

With continued reference to FIG. 4, each cap 42 has an engaging surface 15 which presents pliant ridges 46 which are somewhat deformed, when subjected to pressure so as to form a seal as will be subsequently more fully described.

An upper blood port element generally designated 52 and a lower blood port element generally described as 54 are disposed in apertures '48 and 50, respectively. Clearly, if desired, port element 52 could be used with both apertures 48 and 50, it being understood that both reference blocks would have the corresponding configuration of block 70. It may also be desirable for port element 54 to be used with both apertures 48 and 50, it being understood that corresponding reference block 84 would be used with both port elements. The two different configurations of port elements 52 and 54 are shown for purposes of illustration only.

Blood port elements 52 and 54 are preferably formed of rigid plastic material and in plan view have the shape, essentially, of a regular octagon. The generally flat central body of the elements 52 and 54 has a raised portion 57 or 59 respectively which tapers gradually from the central to become flush with the edges 65. If desired, the raised portion may have a plurality of V-shaped grooves 61 (see FIG. 2) which reduce likelihood of blood leakage around the elements 52 and 54 due to capillary action. Also, capillary action can be reduced by forming notches 63 in edges 65. As best shown in FIG. 4, a passageway 56 traverses the length of the blood port element 52 and opens at a forwardly projecting coupling 58 and at an elliptical orifice 60. A cap 62 may be placed over the coupling 58 to preserve sterility of the blood port passageway 56. It has been found helpful to secure the cap to the port element 52 such as with a tether 64.

As previously mentioned, two ways of orienting the position of the blood port elements are shown in the figures. Upper blood port element 52 is provided with a reference tab 72 which is formed as an extension of one of the sides of the octagon adjacent the coupling 58. The reference tab 72 has two apertures 66. As shown more clearly in FIG. 3 in the assembled condition, apertures 66 are engaged by the dowels '68 located in the reference block 70.

In the embodiment illustrated in FIG. 3, the reference tab 72 is situated upon the upper surface 74 of the reference block 70. If desired, the pegs 68 may be located on a recessed surface (not shown) so that the tab 72 is flush with the upper surface 74 of the reference block 70.

This arrangement is readily apparent by reference to FIG. 2. which illustrates port element 54 situated upon reference block 84. Port element 54 is essentially identical to port element 52 except that the reference tab 76 of the port element 54 is somewhat shorter than the reference tab 72 and includes only a single aperture 77 into which reference dowel 82 may be engaged. Also, the side edge 80 and front edge 81 of the tab 76 are situated in the recess 79 defined in the block 84 so that the tab 76 is flush with the upper surface 86. Because of the close fitting relationship between the sides 80 and 81 of the tab 76, and the shoulders of the recess 79, lateral movement of the port element 54 is precluded.

In the assembled relation, both of the port elements 52 and '54 are first inserted into a tubular membrane 116, as shown best in FIG. 3. The membrane is folded along the sloping forward edges of the port elements 52 and 54 and the port elements are then situated upon the corresponding reference blocks 70 and 84 adjacent apertures 48 and 50. It will be observed that the smooth contoured surfaces 57 and 59 of the corresponding blood ports 52 and 54 will be situated immediately between the contoured portions 41 of caps 42. When the slides 36, 38 and 40 are thereafter compressed together, the port elements will be assembled as shown in FIG. 4. In the illustrated embodiment, the port elements 52 and 54 project laterally behind the slides 36, 38 and 40 into the point support plate (not shown in FIG. 4). Accordingly, the point support plate 112 (shown in FIG. 5) has a contoured recess 1'14 which essentially matches the configuration of the trailing end of blood ports 52 and 54. The recess 114 has a constructed portion 117 which again tapers outwardly at 119 to form a pathway for blood emerging from the point support plate toward the elements 52 and 54 through the constriction 117.

Pressure is exerted through the slides 36, 38 and 40 with an improved clamping mechanism generally designated 88, shown in FIG. 1, as will now be more particularly described.

The clamp assembly 88 comprises two essentially identical brackets 90 mounted upon the end wall 26. Brackets 90 preferably have an elongated slot 92 through which the shank (not shown) of a thumb screw or bolt 94 passes. The elongation of slots 92 advantageously accommodates vertical adjustment of the position of brackets 90 relative to the upper surface 30 of side wall 26. Furthermore, once the desired vertical position of the brackets 90 has been established, the bolts 94 can be tightened so as to preclude additional vertical movement until such time as adjustment is needed, as will be hereinafter more fully described.

Each of the brackets 90 has a looped end 91 which carries a portion of the length of a shaft 96. The shaft 96 is rotatable in the loop ends 91 of brackets 90 and preferably projects laterally beyond one of the brackets so as to be disposed across the upper surface 28 of the side Wall 24. A lever handle generally designated 100 is integrally joined to the shaft 96 at 99. The lever handle 100 has a downwardly projecting offset portion 106 which, when desired, will rest flat upon the upper surface 28 of the vessel wall 24. The offset portion 106 is continuous with an upwardly directed end 104 which can be easily grasped between the fingers and arcuately moved about the axis of shaft 96 so that the shaft will rotate in the brackets 90. Preferably, the shaft 96 has outwardly projecting couplings 101 integral therewith, the couplings 101 being displaced only slightly out of alignment with the handle 100. A cylindrical bearing 98 is rotatably carried on pins (not shown) mounted in the couplings 101. The cylindrical bearing 98 is adapted to impinge upon the upper surface 37 of slide 36. Thus, when the slide 36 is in the assembled position, a downward force can be exerted through slides 36, 38 and 40 by exerting a rotational or torque force through the bearing 98 by pressing the handle 100 downwardly until the offset portion 106 rests upon the surface 28.

It is presently preferred that the offset portion 106 be provided with an elongated slot 108 through which the elongated head of a keeper 110 passes. Thereafter, the keeper can be rotated 90 from the illustrated position to maintain the handle in the downward position. The actual amount of force directed through the bearing 98 to the slides 36, 38 and 40 can be determined by the vertical position of the brackets 90. If it is desired to increase the force, the thumb screws 94 can be loosened and the brackets displaced downwardly relative to the end wall 26. Conversely, the pressure on the slides 36, 38 and 40 can be reduced by loosening bolts 94 and displacing brackets 90 upwardly, as shown in FIG. 1, so that less pressure is exerted upon the slides when the handle 100 is in the down position.

The presently preferred method The method of assembling port elements 52 and 54 in the hemodialyzing vessel 22 can best be understood by reference to FIG. 1. Initially, port elements 52 and 54 are inserted into the interior of the tubular membrane 116 (FIG. 3) and the membrane is folded over the leading edges of the port elements substantially as shown in FIG. 3. If desired, the membrane may be tacked so that the port element is not inadvertently separated from the membrane. The membrane and port elements secured in each end of the membrane are thereafter sterilized according to any desirable technique, such as, for example, exposing the membrane and port elements to ethylene oxide.

With the membrane 116 and port elements 52 and 54 sterilized, the port element 52 is situated in the aperture 50 in the end 26 of vessel 22 so that the coupling 58 projects away from the vessel end 26 and so that the membrane 116 is interior of the vessel 22.

The port element 54 is then properly oriented in the aperture 50 by threading the dowel 82 into the reference tab 76 as shown best in FIG. 2. In this position, the port element 54 is properly oriented in the aperture 52 and is situated so that the smoothly contoured body 59 rests upon the correspondingly contoured portion of the cap 42 secured to the slide 40. Thereafter, the central slide 38 is inserted through the slot 32 by inserting the slide 38 at the upper edge 30 of the end 26. Because the position of the port element 54 has been properly referenced upon the reference block 84, the contoured portion 41 at the bottom edge of the slide 38 will be received in mating relation with the contoured surface 59.

Thereafter, the membrane 116 is stretched in a conventional way over the point support structure interior of the vessel 22. The port element 52, with the membrane 116 attached, is then inserted through the aperture 48 in the end wall 26 as shown best in FIG. 4. The port element 54 is allowed to rest upon the contoured surface of end cap 42 situated in the upper edge of the center slide 38.

The position of port element 52 is fixed when the reference tab 72 is placed upon the dowels 68 in reference block 70 (see especially FIG. 3).

When the port element 52 has been properly referenced upon block 70, the uppermost slide 36 is inserted into the slot 32 so that the contoured cap 42 engages the smooth surface 57 of the port element 52. Importantly, a fluidtight seal is developed simultaneously between the membrane 116 and the corresponding blood ports 54 and 52 when downward pressure is exerted through the slides 36 and 38. The downward pressure is applied to the clamp assembly 88.

The lever handle 100 is rotated counterclockwise about the axis of shaft 96 so that the cylindrical bearing 98 is brought to bear on the upper surface 37 of the slide 36. Continued downward pressure on the lever handle 100 will cause a downward force to be exerted through the slides 36 and 38 so as to form a fluid seal between corresponding portions of the membrane 116 and the port elements 52 and 54. If greater pressure is desired to improve the fluid seal, the bolts or thumbscrews 94 can be loosened so that brackets 90 are displaced downwardly a short distance. When the bolts 94 are thereafter tightened, a greater force will be exerted through the hearing 98 when the lever handle 100 is secured in position by keeper 110.

Occasionally, in the assembly process, blood in the membrane 116 may have a tendency to leak slightly around the blood port 52 or 54. In order to prevent discoloration of all of the dialysate in the vessel 22, the blood may be conducted away from the blood port to a separate receptacle along the channels 49 and 51 as shown in FIG. 4. It is preferable to maintain the dialysate in the vessel 22 clear because visible blood in the dialysate has historically been regarded as the most clear indication of a membrane rupture.

The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

What is claimed and desired to be secured by United States Letters Patent is:

1. A port assembly comprising in combination:

an exterior vessel;

a guideway extending along the length of one of the walls of the vessel, opening to the interior of the vessel and opening at least at one edge;

at least one slide member, slidably displaceable along a plane parallel to the plane of the one wall and carried within the guideway;

a generally fiat port element, part of which is adapted to be engaged by the slide member; and

means extering a compressive force upon the port element through the slide member in a direction essentially normal to the generally flat surfaces.

2. A port assembly as defined in claim 1 wherein the slide member comprises a pliant strip which conforms to the shape of the port element when the compressive force is exerted.

3. A port assembly as defined in claim 2 wherein the pliant strip is contoured to match the contour of the port element.

4. A port assembly as defined in claim 1 wherein said port element comprises a generally fiat polygonally shaped body and an outwardly projecting coupling member and a through-bore extending from the tip of the coupling member to the trailing end of the body.

5. A blood port assembly as defined in claim 1 wherein said exterior housing comprises a platform having at least one upwardly directed dowel and wherein said port element comprises a tab having an aperture therein adapted to mate with the dowel, the dowel and aperture cooperating to determine a desired position for the port element relative to the exterior housing.

6. A port assembly as defined in claim 5 wherein said platform comprises a recessed portion, the sides of the recess cooperating with the peg to limit relative movement of the port element and the exterior housing.

7. A port assembly as defined in claim 5 wherein said platform comprises at least two side by-side upwardly directed pegs.

8. A port assembly comprising in combination:

an exterior vessel;

a guideway in one of the walls of the vessel opening to the interior of the vessel and at least one edge; at least one slide member displaceably carried within the guideway;

a port element, part of the which is adapted to be engaged by the slide member; and

exerting means comprising a lever for exerting a downward force on the slide member when the lever handle is rotated to a predetermined first position; a fulcrum mounted upon the exterior housing, the fulcrum being adjustable in position so that any one of a variety of predetermined downward forces is exerted when the lever handle is in the first position; and a lever bearing through which the force exerted upon the handle is transferred to the slide member, the lever bearing being moved completely out of the path of the slide member when the handle is moved to a second predetermined position. A port assembly comprising: a port element comprising a generally flat body and an outwardly projecting coupling integral therewith, a passageway extending through the body and the coupling and opening at the trailing end of the body and at the tip of the coupling, and a laterally rigid reference tab integral with the body adjacent the coupling; and stationary reference means adapted to define a predetermined orientation of the port element when the reference tab on the port element is aligned with the reference means.

10. A method of securing a generally fiat blood port element into a predetermined fixed position relative to an extracorporeal hemodialyzer, the steps of:

forming a laterally rigid reference tab on the blood port element;

associating the reference tab on the blood port element with corresponding referencing means carried by the hemodialyzer so that the blood port element assumes a predetermined orientation when the reference means on the blood port element is aligned with the corresponding referencing means on the hemodialyzer; and

securing the blood port element so that the predetermined orientation is fixed.

11. A method as defined in claim 10 wherein said forming step comprises perforating the tab integral with the blood port element in at least one location and wherein said associating step comprises placing the perforated portion of the tab over an upwardly directed dowel mounted upon the hemodialyzer.

12. A method as defined in claim 11 wherein said associating step comprises placing the perforated reference tab upon a referencing block carried by the hemodialyzer so that at least one edge of the tab aligns with a corresponding edge on the referencing block.

13. A method of communicating blood into and out of the membrane of an extracorporeal hemodialyzer, the steps of:

inserting a generally flat blood port element into one end of a tubular membrane so that an outwardly projecting coupling member and a reference tab are exposed to the exterior of the membrane; folding the membrane around the body of the blood port element while allowing the coupling member and the reference tab to remain exposed; placing the reference tab in alignment with stationary companion referencing means carried by the hemodialyzer so as to place the blood port element in a predetermined orientation; and securing the blood port element relative to the hemodialyzer to maintain the predetermined orientation. 14. A method as defined in claim 13 wherein said securing step comprises interposing the blood port element between displaceable slides and exerting a predetermined compressive force through the slides to the blood port element.

15. A port element comprising: a generally fiat body having a hollow passageway from the trailing to the leading end thereof; a hollow coupling membenintegral with the body and 20 forming a continuation of the passageway, the coupling member being offset from the leading end of the body;

References Cited UNITED STATES PATENTS Rojehak et al. 2l0321 Martinez 21032l Isreeli 210321 Swenson 210321 Rubin et al. 285-326 X FRANK A. SPEAR, JR., Primary Examiner US. Cl. X.R.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent: No. 3 25 492 Dated July 23 1974 Inventor(s) DAVID L. RADFORD It is certified that error appears in the above-identified patent and that said Letters Patent are-hereby corrected as shown below:

Claim 1, line 61, "extering" should be -exerting-;

Claim 10, line 56, "means" should be tab-.

Signed and sealed this 8th day of October 1974-. v

(SEAL) Attest:

c. VARSHALL DANN MCCOY GIBSON Commissioner "of Patents Attesting ffi FORM PO-105O (10-69) USCOMWDC 5 v A U.S. GOVERNMENT PRINTING OFFICE: 1969 O-JiE-SJ. 

